A coalition of evangelical groups plans to spend $400,000 advertising on Christian radio stations to call on Congress to pass a broad immigration overhaul that would grant citizenship to many of the 11 million undocumented immigrants living in the country.

The ads will play in 14 states and 56 congressional districts, mostly represented by Republicans, said Barrett Duke, vice president for public policy and research at the Southern Baptist Ethics and Religious Liberty Commission.

The ad buy represents another August recess salvo by evangelical immigration advocates to persuade wavering House Republicans to support a comprehensive bill, as the Senate did in June (S 744). The latest round brings total ad spending by the Evangelical Immigration Table to close to $1 million, part of a broader effort by advocates to “win the recess” and send lawmakers back to the Capitol in September ready to move on immigration legislation.

“They’ll return to Washington knowing they have support at home for taking action on reform,” Duke said during a conference call with reporters Tuesday.

Evangelical groups have been a potent force in this year’s immigration debate, joining the efforts of labor unions and immigrant groups. Although traditionally more conservative, evangelical churches have seen an influx of undocumented parishioners in recent years, leading them to support broad immigration changes.

“Immigrants are part of the membership of all of our groups, and for that reason we care about immigration,” said Galen Carey, vice president of government relations for the National Association of Evangelicals.

But evangelical leaders say the question of immigration is also a “humanitarian” one. Felix Cabrera, pastor at the Quail Springs Baptist Church in Oklahoma City, said undocumented immigrants make up roughly half of his church’s congregation.

“As a Hispanic pastor in the United States, I have to deal with the collateral damage that our broken immigration system brings to my people,” he said, referring to deportations of those here illegally.

“Many are separated from their families, leaving behind U.S.-born children without their parents,” he said. “The Bible doesn’t call me to judge the reasons why immigrants arrive to this country. The Bible calls me to love them and welcome them.”

Over the past few weeks, immigration advocates have held rallies and shown up at lawmakers’ town hall meetings across the country, trying to show a groundswell of support for their position. Civil rights groups are also planning to celebrate the 50th anniversary of Martin Luther King Jr.’s “March on Washington” next week with rallies that tout their backing for immigration legislation.

The last time Congress went home for August in the midst of an immigration debate, in 2006, opponents of an overhaul packed district meetings and succeeded in killing momentum for the legislation.

That scenario does not appear to be unfolding this time, with many Republicans striking a more moderate tone on immigration, even if they’re not ready to support a path to citizenship for all 11 million undocumented immigrants.

“The big story of this August recess is we haven’t seen what some have predicted, where members of Congress would be heckled into inaction,” Carey said. “It’s been a muted voice, but the pro-immigrant voice has been rather prominent in many of the town halls that we have observed.”

When House GOP leaders return, they’ll face decisions on whether and how to move ahead this fall with the five immigration bills that have cleared the Judiciary and Homeland Security committees. Those measures deal with border security (HR 1417), state and local immigration enforcement (HR 2278), employment verification (HR 1772), agricultural guest workers (HR 1773) and high-tech worker visas (HR 2131).

Majority Leader Eric Cantor and Judiciary Chairman Robert W. Goodlatte, both Virginia Republicans, are working on another bill, tentatively labeled the “KIDS Act,” that would grant legal status or citizenship to young people brought to the country illegally as children.